Science Buddies: "Ask an Expert"

Hello,

I have followed your tutorial for the self driving line following robot. (https://www.sciencebuddies.org/science- ... p023.shtml). I think this would be an excellent project for my robotics students. However, I am having difficulties getting the robot going. I have followed the help tips and the diagrams and triple checked everything and it still won't turn on. It seems the mosfet is not turning on to drive the motor. The infrared LED's are lighting up when looked at with a digital camera. I have purchased all of the components as outlined in the tutorial. Does anyone have any suggestions or has anyone come across a similar problem/solution???

Hi KHart,

I forget if the forum allows you to upload pictures, but if it does, can you upload some pictures of your breadboard, taken from a top-down view (like Figure 21 in the procedure of the project)? That might help me spot any problems. If you can't upload them to the forum, a link to any third-party image hosting site would work too. A couple photos from *slightly* different angles would help, since tall components on the breadboard (like the MOSFETs) can obscure which holes things are plugged into. I have done classes with this robot (and our other projects) before, and 99% of the time when something isn't working, it's just because one wire is misplaced somewhere...so even when you've double and triple checked, it's nice to just have a second set of eyes on the breadboard.

Also, FYI we are launching a new kit for this project in a couple weeks. It will contain all the parts to do the line following robot plus three other projects that all use the same chassis:

https://www.sciencebuddies.org/science- ... p022.shtml

https://www.sciencebuddies.org/science- ... p024.shtml

https://www.sciencebuddies.org/science- ... p028.shtml

The directions for the projects will be revamped (and we hope, easier to follow). Of course, you can still buy all the parts individually instead, but I thought you might be interested in the kit if you're considering doing this for a whole class.

Thanks,

Ben